[BUG]: Docstring Types for Numpy/Eigen Matricies

[InvincibleRMC]

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What version (or hash if on master) of pybind11 are you using?

51c2aa16de5b50fe4be6a0016d6090d4a831899e

Problem description

Hello there. The generated docstring for eigen tensors things look like the following numpy.ndarray[numpy.float64[3,2]]. I was curious why this was decided since this is not valid Python typing. It should be something like numpy.typing.NDArray[numpy.float64]. I assume the [3, 2] are supposed to be suggesting shape information but, that is still not supported https://github.com/numpy/numpy/issues/16544. The generated syntax causes stubgen to crash. I'm fine fixing it I just wanted more information on what exactly was going on here.

Reproducible example code

Running mypy stubgen on the test cases.

stubgen -p pybind11_tests.eigen_tensor

Is this a regression? Put the last known working version here if it is.

Not a regression